Fix pluralization

Fix annoying "There are 1 nodes available in the system." when you only
have one node in the system.
Use placeholder text for group field

Instead of using an invalid default value (no spaces allowed).
Just count the physical network interfaces

Use node["crowbar_ohai"]["detected"]["network"] for counting the NICs as that
one just includes the physical interfaces. node["network"]["interfaces"] also
contains loopback, bonding, bridges and so on.
Merge pull request #547 from rhafer/fix/nic-count

Just count the physical network interfaces
Recognize Bochs hardware as virtual
Merge pull request #545 from jamestyj/release/pebbles/master-fix-pluralization

Fix pluralization
Fix crash in crowbar command line tool when no user/password is defined

Arguably it can be seen as a bug in the rubygem, but it's easy to fix
from here.

CROWBAR_KEY not set, will not be able to authenticate!
Please set CROWBAR_KEY or use -U and -P
/opt/dell/bin/barclamp_lib.rb:484:in `run_sub_command': undefined method `tr' for nil:NilClass (NoMethodError)
        from /usr/lib64/ruby/gems/1.8/gems/net-http-digest_auth-1.1.1/lib/net/http/digest_auth.rb:74:in `auth_header'
        from /opt/dell/bin/barclamp_lib.rb:126:in `authenticate'
        from /usr/lib64/ruby/1.8/net/http.rb:543:in `start'
        from /usr/lib64/ruby/1.8/net/http.rb:440:in `start'
        from /opt/dell/bin/barclamp_lib.rb:109:in `authenticate'
        from /opt/dell/bin/barclamp_lib.rb:138:in `get_json'
        from /opt/dell/bin/barclamp_lib.rb:250:in `proposal_list'
        from (eval):1:in `run_sub_command'
        from (eval):1:in `eval'
        from /opt/dell/bin/barclamp_lib.rb:484:in `run_sub_command'
        from (eval):1:in `run_sub_command'
        from /opt/dell/bin/barclamp_lib.rb:488:in `eval'
        from /opt/dell/bin/barclamp_lib.rb:484:in `run_sub_command'
        from /opt/dell/bin/barclamp_lib.rb:488:in `run_command'
        from /opt/dell/bin/barclamp_lib.rb:493:in `main'
        from /opt/dell/bin/crowbar_crowbar:21
Merge pull request #546 from jamestyj/release/pebbles/master-fix-group-field-placeholder

Use placeholder text for group field
Merge pull request #549 from vuntz/fix-crash-on-non-auth

Fix crash in crowbar command line tool when no user/password is defined
Merge pull request #548 from vuntz/bochs-as-virtual

Recognize Bochs hardware as virtual
Replace github.com/dellcloudedge mentions with github.com/crowbar
Rename KEEP_ME file to KEEP_THIS

We already have several KEEP_THIS files, so make this consistent. This
makes it easier to remove all these files.
Merge pull request #553 from vuntz/replace-dellcloudedge

Replace github.com/dellcloudedge mentions with github.com/crowbar
Merge pull request #554 from vuntz/consistent-KEEP_THIS

Rename KEEP_ME file to KEEP_THIS